全文获取类型
收费全文 | 97篇 |
免费 | 6篇 |
国内免费 | 7篇 |
专业分类
林业 | 4篇 |
农学 | 2篇 |
12篇 | |
综合类 | 46篇 |
农作物 | 5篇 |
水产渔业 | 11篇 |
畜牧兽医 | 11篇 |
园艺 | 6篇 |
植物保护 | 13篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 12篇 |
2011年 | 6篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1991年 | 1篇 |
排序方式: 共有110条查询结果,搜索用时 31 毫秒
51.
52.
The ability of Fusarium oxysporum (PSM 197), a potential mycoherbicide for control of Striga hermonthica, to control different Striga species (S. hermonthica, S. asiatica and S. gesneroides) and another parasitic weed, Alectra vogelli, was investigated under glasshouse conditions. Significant reductions in the total number of emerged plants of S. asiatica (91.3%), S. gesneroides (81.8%) and S. hermonthica (94.3%) were achieved in the presence of F. oxysporum (PSM 197). The pathogen only caused a reduction of 8.5% in A. vogelli. This high susceptibility of the three Striga species provides a possible opportunity to control these parasites simultaneously with this mycoherbicide. 相似文献
53.
54.
AIM: To investigate the effects of Centella asiatica extracts on the cell cycle and intracellular free calcium ( i) in spleen lymphocytes. METHODS: Centella asiatica was extracted with alcohol and different organic solvents. Sephadex-LH20 gel column chromatography was applied for further purification. To screen the active constituents, the scavenging ability of the fractions generated by elution of chromatography against radicals of OH·, DPPH· and their anti-proliferative effects on spleen lymphocytes were measured. To assess the cell cycle and i in spleen lymphocytes, flow cytometry was performed. RESULTS: The D fraction eluted from the crude extract of Centella asiatica was obtained, which had strong suppressive effect on lymphocyte proliferation and decreased the i of the cells in a dose-dependent manner. The cell cycle of the spleen lymphocytes arrested at S and G2/M stages when treated with the D fraction. CONCLUSION: The effects of Centella asiatica for lowing i and arresting cell cycle at S and G2/M stages of spleen lymphocytes are responsible for its anti-proliferative activitiy. 相似文献
55.
56.
月鳢仔鱼耳石的荧光标记及其日轮确证 总被引:1,自引:0,他引:1
利用茜素络合物对体长(9.99±0.56)mm的月鳢(Channa asiatica)仔鱼耳石进行浸泡标记试验。结果表明,经荧光显微镜检测,80 mg/L、100 mg/L和120 mg/L的溶液浸泡24 h后均可以在月鳢仔鱼的耳石上形成橘红色标记环,星耳石、微耳石和矢耳石的标记率均为100%;其中,以星耳石标记环荧光强度最大,且在普通光学显微镜下也可观察到紫红色标记环。经100 mg/L和120 mg/L溶液浸泡后,月鳢仔鱼在其后饲养阶段出现较高的死亡率,显示高浓度茜素络合物溶液对月鳢仔鱼有一定毒性。标记后星耳石上的新增轮纹数(N)和饲养天数(D)密切相关,其线性方程为:N=0.9291D-0.2974(R2=0.9793,n=64,P<0.01),斜率0.9291与1无显著差异(P>0.05),表明星耳石上的生长轮即为日轮。研究表明,在追踪月鳢仔鱼迁移行为时,可采用80 mg/L的茜素络合物溶液对其星耳石进行染色标记。 相似文献
57.
利用透射电镜技术研究了大车前(Plantago major L.)合子及其原胚发育特点。结果如下:大车前胚胎发育类型为柳叶菜类型。合子发育过程中,合点端的细胞壁逐渐形成,合子体积增大,极性增强,质体内贮藏淀粉。合子分裂通常发生在初生胚乳核分裂之后,第1次横分裂形成基细胞和顶细胞。基细胞经多次分裂形成单列细胞构成发达的胚柄;顶细胞多次分裂形成胚体,胚体细胞核大,核仁明显,细胞器的种类与数量多,呈现旺盛分生能力,具有很高的代谢活性。原胚发育过程中,小球胚初期,胚胎发育的营养物质主要来自合子储存的以及胚柄吸收并转运的营养物质;小球胚至中球胚期,胚柄组织迅速发育,依赖发达的胚柄自珠被组织吸收营养物质并转运至胚体;大球胚后期,胚柄开始解体,胚体外围细胞吸收胚乳的降解物作为胚胎发育所需营养物质。 相似文献
58.
车前种质资源遗传多样性ISSR分析 总被引:1,自引:0,他引:1
[目的]研究江西、湖南、湖北等7个省份的车前种质资源的遗传多样性。[方法]采用ISSR技术,对28份车前样品进行遗传多样性和亲缘关系分析。[结果]从40条引物中共筛选出16条可用于车前遗传多样性分析的ISSR引物,共扩增出131条带,其中多态性条带(PPB)有107条,占81.7%。ISSR数据分析显示,多态性位点百分率(P)为75.3%;平均等位基因观测数为0.071 3;有效等位基因数为0.299 0;Nei,s基因多样性指数(H)为0.360 1;Shannon多态性信息指数(I)为0.535 4。[结论]车前种质资源遗传多样性的地理差异较为明显;野生种与栽培种基因型差异较大。 相似文献
59.
Plants are often grazed resulting in a sudden and significant removal of shoot tissue, which decreases photosynthesis and changes C allocation between within the plant. From results obtained in percolated sand it is possible to demonstrate an increase of rhizodeposition within few days after defoliation followed by a decrease of rhizodeposition. The aim of our study was to test if this pattern can be also observed for plants grown in soil. We grew Plantago arenaria in microcosms and defoliated half of them after 45 d. Half of the defoliated and non-defoliated microcosms were harvested 1.5 d, and the other half 8.5 d, after defoliation. We observed an increase of microbial biomass 1.5 d after defoliation followed by a decrease assessed 8.5 d after the treatment. In parallel, soil soluble C and the metabolic quotient of the microbial biomass first decreased and then increased at the second harvest reaching values equivalent to those of the non-defoliated treatment. Based on these results together with results obtained in artificial soil, we conclude that the defoliation of P. arenaria grown in soil leads to a transient peak of root exudation. 相似文献
60.
[目的]了解月鳢和乌鳢的生化遗传特性,为其品种鉴定提供理论依据。[方法]采用聚丙烯酰胺凝胶垂直梯度电泳法对月鳢和乌鳢的眼、肌肉、心脏、脾、脑和肾中的2种同工酶进行分析。[结果]月鳢肾脏、脾脏、脑和心脏的苹果酸脱氢酶(MDH)图谱有很清晰的4条带,且带型相同、活性相当;其眼组织的MDH图谱有5条带,肌肉组织的MDH带型分布表现出明显活性区。鸟鳢肾脏、脾脏、脑、肌肉和心脏的MDH图谱有很清晰的4条带;其眼组织的MDH图谱有5条带。月鳢和鸟鳢不同组织中酶的图谱数量一样,但类型不同。在鸟鳢6种组织中,眼睛的MDH表达量最大,而月鳢各组织的MDH表达量差异不大。乳酸脱氢酶(LDH)在乌鳢中的表达量高于月鳢。[结论]硬骨鱼类同工酶系统具有明显的组织特异性和物种特异性,其变化可更直接、正确地反映生物体的差异。 相似文献